Security systems are known in the art to prevent crimes and to notify security personnel of when an intrusion, or other triggering event such as a fire, is occurring.
Oftentimes, such security systems are connected to a telephone line to dial out an alert. Because many locations have a single telephone line, if the telephone of the single telephone line is lifted off the hook, inadvertently by a user, or intentionally by an intruder, or is otherwise in use, a security system connected to the telephone line is not able to dial an alert out to security personnel.
The following are examples of prior art which attempt to overcome this problem. U.S. Pat. No. 5,923,732 describes a security alarm system having a switch to command the telephone line. The main control unit of the system is connected directly to an incoming telephone line and outputs are provided to connect it to a telephone. The unit is capable of receiving alarm signals from remote sensing means. Upon receipt of the alarm signal a processing means disconnects the telephone extensions from the incoming telephone line and allows the system to seize control of the incoming telephone line for a processing means within the main control unit to execute a predetermined response, such as sending out alarm messages. A panic dial out alarm such as a telephone input of a code will override a line dead or line busy alarm. The seizing unit sends out alarm messages through the telephone line.
U.S. Pat. No. 6,081,546 provides that with the detection of an alarm condition at a security alarm system that requires a communications link, line seizure is effected via a seizure circuit serially connected between each telephone handset and the telephone line. A line monitor within a system controller shorts the telephone line to drive any conducting line seizure circuits into a non-conducting condition that is maintained sufficiently long to permit the system controller to gain control of the line. As above, the seizing unit is a part of the system controller unit responsible for sending out alarm messages.
U.S. Pat. Nos. 5,930,355 and 5,764,729 describe tamper protection devices for protecting a telephone operated security alarm system. In U.S. Pat. No. 5,764,729, the protection device includes a vibration sensor which, when activated, informs a security monitor of the activation before an intruder can disable the alarm. In U.S. Pat. No. 5,930,355, the protection device includes a shield which, when tampered with, will trigger an alarm.
In U.S. Pat. No. 5,465,297, a telephone seizure unit operates so that when the automatic dialer is on-hook, the telephone line seizure unit will be transparent to the telephone systems and the telephones will operate normally. When the automatic dialer goes off-hook the telephone line seizure unit disconnects any telephone in use, which thereby allows the automatic dialer unimpeded access to the telephone lines for a pre-determined period of time to send out the alarm detection signal to a central security office.
In U.S. Pat. No. 4,390,750, auxiliary equipment creates an off-hook condition when an alarm condition occurs. If an abnormal condition occurs at the premises, the condition is sensed by one of the sensors, which transmits a signal to the auxiliary equipment. The equipment in response creates a temporary off-hook condition and transmits alarm report signals to the central office and then goes back on-hook. The off-hook condition need last only a few seconds for the alarm report to be completed.
Additionally, systems which allow for user flexibility in alert notification and monitoring of occurrences of specific conditions are also desired.
U.S. Pat. No. 6,147,601 describes a system and a method for monitoring remote equipment. A sensor is in communication with a piece of remote equipment, and an interface unit having a message generating mechanism is connected to the sensor. A central computer server is in communication with the interface unit and is adapted to receive messages generated by the interface unit. When the sensor detects an exception in the piece of remote equipment the interface unit generates an incoming exception message and forwards the message to the server. The server forwards the message to at least one user-defined communication device.
It is thus an object of the present invention to provide, a telephone seizure unit for allowing a system to dial out when a telephone is in an off-hook position.
It is a further object of the present invention to allow for user flexibility in a detection and notification system.